Heated manifold

ABSTRACT

A quick heat intake manifold for evaporating fuel droplets during cold engine starts includes a depressed hot plate assembly forming a fuel evaporation chamber located below carburetor riser bores in the intake manifold, the plate being located in an exhaust crossover passageway to be heated by exhaust from the engine during cold start. A cover is located over the evaporation chamber including openings therein for directing fuel droplets from the carburetor to the chamber, bimetallic vanes located on the cover have a cold start position wherein the vanes divert air-fuel mixture into the evaporation chamber and a warm engine position wherein the vanes reduce flow of air-fuel mixture through the evaporation chamber to prevent excessive heat transfer to the air-fuel mixture during warm engine operation.

United States Patent Cole June 3, 1975 HEATED MANIFOLD [75] Inventor: Edward N. Cole, Bloomfield Hills,

Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Sept. 4, 1973 [21] Appl. No.: 394,186

[52] US. Cl. 123/122 AC; 123/122 H [51] Int. Cl. .1 F02m 31/00 [58] Field of Search... 123/122 AB, 122 AC, 122 H, 123/133; 261/141; 165/52 [56] References Cited UNITED STATES PATENTS 1,998,497 4/1935 Fulh 123/122 H 2,054,997 9/1936 Vang 123/122H 2,434,192 1/1948 Brown 123/122 H 2,437,724 3/1948 Brown 123/122 H 3,780,715 12/1973 Flitz 123/122 AC Primary ExaminerCharles J. Myhre Assistant Examiner-R. H. Lazaus Attorney, Agent, or FirmJ. C. Evans 57 ABSTRACT A quick heat intake manifold for evaporating fuel droplets during cold engine starts includes a depressed hot plate assembly forming a fuel evaporation chamber located below carburetor riser bores in the intake manifold, the plate being located in an exhaust crossover passageway to be heated by exhaust from the engine during cold start. A cover is located over the evaporation chamber including openings therein for directing fuel droplets from the carburetor to the chamber, bimetallic vanes located on the cover have a cold start position wherein the vanes divert air-fuel mixture into the evaporation chamber and a warm engine position wherein the vanes reduce flow of air-fuel mixture through the evaporation chamber to prevent excessive heat transfer to the air-fuel mixture during warm engine operation.

4 Claims, 4 Drawing Figures L c )1, k l

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a: a \TY T k W :W if i/ 1 PATENTEDJUH 3 ms Hal l HEATED MANIFOLD This invention relates to vehicle intake manifolds and more particularly to exhaust heated transfer plates in an intake manifold including means for thermostatically controlling induction flow across the plate to produce fuel evaporation during cold starts and to prevent excessive heating of the air-fuel mixture during warm engine operation.

In order to achieve fast temperature rise in an exhaust heated plate for evaporating fuel droplets in an intake manifold during cold engine start, it is desirable to include means for transferring a substantial amount of the energy from the exhaust of the engine to a plate having a low thermal mass during cold engine operation. I

In such a system the heated transfer plate serves to evaporate liquid fuel droplets in the air-fuel mixture from a carburetor prior to passage thereof to the intake valves of the engine.

Such systems must be designed to evaporate the liquid when the engine is cold without appreciably heating the air-fuel mixture when the engine is warm, especially under conditions where the engine is operated under high temperature ambient conditions.

Accordingly, an object of the present invention is to improve quick heat intake manifolds for evaporating liquid fuel particles in an air-fuel mixture from a carburetor prior to passage thereofinto transverse runners of the intake manifold by the provision of a heat transfer insert plate in the intake manifold heated by exhaust flow from the engine; the plate including a low thermal mass and a substantial surface area rapidly heated to a temperature to evaporate fuel droplets accumulated thereon and including means interposed between intake manifold riser bores and the insert plate for defining an induction flow path for diverting induction flow against the intake plate when the engine is cold and responsive to increases in temperature of the engine to divert the induction flow from the heated plate following the engine warm-up therby to prevent excessive heating of the air-fuel mixture to the intake valves of the engine.

Still another object of the present invention is to provide an improved quick heat manifold having an insert plate assembly in the manifold located below carburetor riser bores to form a largesurface area enclosure located in an exhaust crossover passage for receiving energy from the exhaust flow to raise the temperature of the insert so as to evaporate fuel droplets accumulated .in the enclosure; and wherein the assembly includes an enclosure cover having openings therein vertically below the riser bores and bimetallic valve means are included on the cover for selectively opening and closing the openings to divert the air-fuel mixture and droplets therein into the enclosure during cold engine starts for evaporating the fuel droplets prior to passage into the intake valves of the engine, the bimetallic valve means being responsive to a predetermined engine temperature to direct the air-fuel mixture from the heated insert plate to prevent excessive heating of the air-fuel mixture prior to passage into the intake valves of the engine following engine warm-up.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the Drawings:

FIG. 1 is a fragmentary view partially in elevation and partially in section of a carburetor and intake manifold including the present invention;

FIG. 2 is an enlarged vertical sectional view of an exhaust heated manifold insert enclosure for fuel evaporation:

FIG. 3 is a fragmentary, vertical sectional view of an engine manifold including a second embodiment of the invention; and

FIG. 4 is a vertical sectional view taken along the line 4-4 of FIG. 3.

Referring now to the drawings in FIG. 1, an intake manifold 10 is illustrated including a primary carburetor riser bore 12 therein and a secondary riser bore 14 for directing air-fuel mixture from a carburetor 16 having an air cleaner 18 connected thereto with an intake 20 for receiving outside air for passage through the air cleaner 18 and carburetor 16, for flow into the intake manifold 10. The intake manifold 10 includes an induction chamber 22 located below the risers 12, 14 and upper transverse runners 24, 26 for directing air-fuel mixture to the intake valves of the engine. Additionally, the intake manifold 10 includes lower transverse runners 28, 30 supplying air-fuel mixture from the intake manifold 10 to other intake valves of the engine.

In the illustrated arrangement, the intake manifold 10 includes an integrally formed depending portion 32 defining an exhaust heat crossover passage 34 for receiving exhaust from the exhaust manifold of the engine. It includes a cover 36 secured thereto by means of bolts 38 to receive a manifold insert enclosure 40 including means for collecting fuel droplets during engine start and to evaporate the fuel droplets prior to passage thereof through the transverse runners 24, 26, 28, 30.

More particularly, as shown in FIG. 2, the enclosure 40 includes a base defined by an open ended box 42 having a flange 44 thereon secured to a peripheral flange 46 on an enclosure cover 48 that fits within a manifold opening 50 so as to locate a horizontal surface 52 of the cover 48 below the primary riser bore 12. The enclosure 40 is secured to the floor 54 of the intake manifold 10 by suitable fastening means such as screws 56 thereby to fixedly secure the enclosure 40 between the induction passage 22 and the exhaust crossover passage 34. The enclosure 40 is shown press fit in opening 50 to seal between passages 22, 34 it being understood that seal means such as gaskets also might be interposed between enclosure 40 and floor 54 to prevent leaks between the passages 22, 34.

The horizontal cover surface 52 includes a plurality of spaced apart openings 58 therein located below the primary bore 12. Each of the openings 58 has a bimetallic, vane-like valve element 60 associated therewith. More particularly, each of the valve elements 60 is connected at the base 62 thereof to the horizontal cover surface 52 on one side of each of the openings 58 and includes a free end portion 64 located above the openings 58 in a generally upwardly inclined direction faced toward the riser bore 12 when the engine is cold. The elements 60 thus serve to divert fuel droplets from the air-fuel mixture flowing through the riser bore 12 into the induction passageway 22 through the openings 58 thence into a fuel evaporation chamber 66 formed by the box 42 and the cover 48. The fuel droplets will accumulate in the box 42 rather than pass into the intake valves of the engine.

The enclosure 40 is preferably constructed of light sheet metal material having low thermal mass whereby exhaust flow through the passage 34 will quickly heat a bottom wall 68 of enclosure 40 during engine start so that fuel droplets accumulated thereon will evaporate and pass upwardly through the openings 58 for flow through the transverse runners of the intake manifold 10. The configuration of elements 60 serves to catch liquid fuel as it comes from the carburetor and the configuration of the enclosure 40 will maintain the fuel droplets in contact with the heating surface defined by the box 42 until the fuel droplets are evaporated and thereby minimize the emissions of unburned hydrocarbons passing from the engine.

A further feature of the present invention is that once the engine reaches a warm operating condition, each of the valve elements 60 will deflect from the solid line position shown in FIG. 2 in a downward direction to the dotted line position in FIG. 2 to cover the openings 58. Concurrently, the carburetor will be operated in a warm engine mode with the choke off thereby to reduce the flow or raw fuel into the induction passage 22. Additionally, the intake manifold will have an ele vated temperature that will serve to evaporate any raw fuel that passes from the carburetors 16 into the intake manifold 10.

During warm engine operation, it is undesirable to have substantial heat transfer from the exhaust heated enclosure 40 to the air-fuel mixture passing to the intake valves of the engine through the induction passageway 22. Accordingly, the valves 60 are responsive to the increased engine temperature to deflect from the solid line position shown in FIG. 2 to their dotted line closed position where they will cover the openings 58 and produce a dead space defined by the enclosure chamber 66 which effectively reduces heat transfer from the crossover passage 34 into the main induction passage 22. Exhaust flow heat is thereby isolated from induction flow to prevent excessive heating of the airfuel mixture. Furthermore, the arrangement will effectively isolate the exhaust flow following engine warmup without creating excessive back pressure conditions in the exhaust crossover passageway 34. In the past, it has been proposed to include an additional heat riser valve in the exhaust crossover passageway to reduce heat flow to an insert hot plate in an intake manifold. Such heat riser valves, however, must operate in a dirty exhaust flow environment which is eliminated by use of the valves 60 in the present invention. Another proposal to restrict heat transfer through an insert plate in an intake manifold is to reduce the crossover passageway to restrict flow therethrough. Such systems, however, can create excessive back pressure and poor driveability during cold engine, full throttle operation. The valves 60 of the present invention also eliminate this problem. I

A second embodiment of the invention is illustrated in FIGS. 3 and 4. FIG. 3 shows an intake manifold 70. It includes a pair of carburetor riser bores 72, 74, FIG. 4, formed through a carburetor pad 76 on the top 78 of manifold 70. Each bore 72, 74 communicates with an induction passage 80 which communicates with a pair of transverse runners 82, 84 for supply of air-fuel mixture from the carburetor to the intake valves of the engine,

An exhaust crossover plate 86 with a flange 88 connected to manifold has a passage 90 therein with an inlet 92 and an outlet 94 adapted to be connected between the outlet of an exhaust manifold of the engine and the exhaust pipe thereof for continuous exhaust flow therethrough during engine operation.

As in the first embodiment. the manifold 70 includes an exhaust heated insert closure assembly 96 therein including a box-like base 98 sealingly supported within an opening 100 through the base 101 of the manifold 70 below the riser bores 72, 74. It further includes a cover 102 thereon with a central inlet opening 104 therethrough that leads to an exhaust heated evaporation chamber 106. The cover further includes openings 108, therein that lead from the chamber 106 to direct flow therefrom into each of the transverse runners The enclosure 96 is sealingly located with respect to the manifold base 101 to seal between the induction passage 80 and the exhaust crossover passage 90. Additionally, it includes a bottom surface 112 thereon to accumulate fuel droplets during cold engine start. Surface 112 is located in the crossover passage 90 so as to receive exhaust heat therefrom during cold engine start to evaporate fuel droplets accumulated thereon.

In this embodiment of the invention, a pair of bimetallic valves 114, 116 are located on the cover 102 on either side of the central opening 104 and have a cold position wherein they are located vertically with respect to the cover 102 so as to block direct flow from the carburetor riser bores 72, 74 to the transverse runners 82, 84. Thus, during cold engine starts the air-fuel mixture will pass downwardly through the riser bores 72, 74 and will be directed by the upstanding bimetallic valves 114, 116 through the central opening 104 into the evaporation chamber 106. The enclosure surface 112 will divert the intake flow upwardly through the outlet openings 108, 110 for passage into the transverse runners 82, 84. At the same time, heavier fuel droplets will accumulate within the enclosure and will be evaporated by contact with the surface 112 thereofand will pass upwardly into the evaporation chamber 106 to flow with the gaseous component of the air-fuel mixture during cold start through the outlets 108, 110.

In this embodiment of the invention when the engine warms up, the bimetallic valve elements 114, 116 will deflect downwardly into the dotted line position shown in FIG. 3 to overlie the outlet openings 108, 110. Inlet flow will thereby pass downwardly against the cover of the enclosure 96 and be drawn directly into the transverse runners 82, 84 so as to avoid direct heat transfer contact between the air-fuel mixture and the exhaust heated metal of the enclosure 96. Proper selection of the dimensions of the inlet 104 restricts flow into the evaporator enclosure 106 when the valve elements are in their dotted line position thereby to reduce exhaust heat of the induction flow under warm engine operating conditions.

As was the case in the first embodiment, the arrangement disclosed in FIGS. 3 and 4, eliminates the need for heat riser valves and further reduces restriction of exhaust flow through a crossover passage for heating a manifold insert during cold engine start conditions.

While the embodiments of the present invention, as herein disclosed, constitute a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

l. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having a carburetor riser bore therein, an induction passage within said intake manifold for receiving air-fuel mixture from the carburetor riser bore, transverse runners in said manifold for directing airfuel mixture from the induction passageway to intake valves of the engine, means including a box having openings for collecting liquid fuel droplets from said riser bore, a heat transfer plate located in said box below the intake riser bores in the floor of the intake manifold, means for heating the heat transfer plate with exhaust flow for raising the temperature thereof upon cold engine start, valve means located in said induction passage between said riser bore and said box openings for diverting intake air-fuel mixture into said box and against said heated plate during cold engine start, said valve means including means responsive to engine temperature for closing said box openings to reduce flow of air-fuel mixture across said heated plate and diverting said flow from the induction passage to the transverse runners when the engine reaches a predetermined temperature thereby to prevent excessive heating of the air-fuel mixture passing from the carburetor to the intake valves of the engine when it is heated to a predetermined temperature level.

2. A heated manifold assembly for use in evaporating fuel particles supplied from a carburetor to an engine during cold engine starts comprising an intake manifold having carburetor riser bores therein for receiving an air-fuel mixture from a carburetor, an induction passage in said intake manifold in communication with said riser bores and including a floor located immediately below said riser bores, transverse runners for directing airfuel mixture from said induction passage to the intake valves of the engine, an opening in said floor, an enclosure supported in said floor and including a base portion thereon and a cover portion thereon forming a fuel evaporation chamber, means surrounding said base portion of said box for directing exhaust flow in heat transfer relationship with said box to heat the interior of said evaporation chamber, said cover including an opening therein for receiving fuel droplets from the riser bore during cold engine starts, valve means on said cover fordiverting downward flow through the riser bores into the evaporation chamber through said opening so as to prevent flow of fuel droplets into the transverse bores during cold engine start, said fuel droplets being heated within the evaporation chamber to be evaporated for return flow through said cover opening and the transverse runners into the engine cylinders, said valve means being responsive to engine temperature to control flow through said cover opening to prevent excess heating of the air-fuel mixture as it pases through said induction passage once the engine has reached a predetermined temperature.

3. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having carburetor riser bores therein and an induction passage for receiving air-fuel mixture from a carburetor, transverse runners in communication with said induction passage for directing the airfuel mixture from the carburetor to the intake valves of the engine, a heat transfer box located below said riser bores in the floor of the intake manifold defining a fuel evaporation chamber, means forming a crossover passageway in said manifold for directing exhaust from the engine in heat transfer relationship with said box to raise the temperature thereof on cold engine start, means forming a cover over said box including a central opening therein underlying said riser bores, said cover including a pair of outlet openings therein for directing evaporated fuel from said evaporation chamber into said transverse runners, bimetallic valve means supported on said cover having a first operative position when the engine is cold to direct air-fuel mixture from the riser bores through the central opening of said cover into said evaporation chamber, thence outwardly of said cover outlets into said transverse runners whereby fuel droplets in the air-fuel mixture during cold engine start are evaporated prior to passage to the transverse runners, said valve means being responsive to a predetermined increase in engine temperature to assume a second operative position to close said outlet openings and to open direct communication between said induction passage and said transverse runners for reducing heat transfer from said box to the air-fuel mixture thereby to prevent excessive temperature increases therein following engine warm-up.

4. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having carburetor riser bores therein and an induction passage for receiving air-fuel mixture from a carburetor, transverse runners in communication with said induction passage for directing the airfuel mixture from the carburetor to the intake valves of the engine, a heat transfer box located below said riser bores in the floor of the intake manifold defining a fuel evaporation chamber, means forming a crossover passageway in said manifold for directing exhaust heat from the engine in heat transfer relationship with said box to raise the temperature thereof on cold engine start, means forming a cover over said box including a plurality of openings therein underlying said riser bores, said cover including a bimetallic valve overlying each of said cover openings supported on said cover and having a first operative position when the engine is cold to divert fuel droplets in the air-fuel mixture from the riser bores into said evaporation chamber whereby fuel droplets in the air-fuel mixture during engine start are evaporated prior to passage to the transverse runners, said valve means being responsive to a predetermined increase in engine temperature to assume a second operative position to close said openings and to block communication between said induction passage and said fuel evaporation chamber for reducing heat transfer from said box to the air-fuel mixture thereby to prevent excessive temperature increases therein following engine warm-up. 

1. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having a carburetor riser bore therein, an induction passage within said intake manifold for receiving air-fuel mixture from the carburetor riser bore, transverse runners in said manifold for directing air-fuel mixture from the induction passageway to intake valves of the engine, means including a box having openings for collecting liquid fuel droplets from said riser bore, a heat transfer plate located in said box below the intake riser bores in the floor of the intake manifold, means for heating the heat transfer plate with exhaust flow for raising the temperature thereof upon cold engine start, valve means located in said induction passage between said riser bore and said box openings for diverting intake air-fuel mixture into said box and against said heated plate during cold engine start, said valve means including means responsive to engine temperatuRe for closing said box openings to reduce flow of air-fuel mixture across said heated plate and diverting said flow from the induction passage to the transverse runners when the engine reaches a predetermined temperature thereby to prevent excessive heating of the air-fuel mixture passing from the carburetor to the intake valves of the engine when it is heated to a predetermined temperature level.
 1. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having a carburetor riser bore therein, an induction passage within said intake manifold for receiving air-fuel mixture from the carburetor riser bore, transverse runners in said manifold for directing air-fuel mixture from the induction passageway to intake valves of the engine, means including a box having openings for collecting liquid fuel droplets from said riser bore, a heat transfer plate located in said box below the intake riser bores in the floor of the intake manifold, means for heating the heat transfer plate with exhaust flow for raising the temperature thereof upon cold engine start, valve means located in said induction passage between said riser bore and said box openings for diverting intake air-fuel mixture into said box and against said heated plate during cold engine start, said valve means including means responsive to engine temperatuRe for closing said box openings to reduce flow of air-fuel mixture across said heated plate and diverting said flow from the induction passage to the transverse runners when the engine reaches a predetermined temperature thereby to prevent excessive heating of the air-fuel mixture passing from the carburetor to the intake valves of the engine when it is heated to a predetermined temperature level.
 2. A heated manifold assembly for use in evaporating fuel particles supplied from a carburetor to an engine during cold engine starts comprising an intake manifold having carburetor riser bores therein for receiving an air-fuel mixture from a carburetor, an induction passage in said intake manifold in communication with said riser bores and including a floor located immediately below said riser bores, transverse runners for directing air-fuel mixture from said induction passage to the intake valves of the engine, an opening in said floor, an enclosure supported in said floor and including a base portion thereon and a cover portion thereon forming a fuel evaporation chamber, means surrounding said base portion of said box for directing exhaust flow in heat transfer relationship with said box to heat the interior of said evaporation chamber, said cover including an opening therein for receiving fuel droplets from the riser bore during cold engine starts, valve means on said cover for diverting downward flow through the riser bores into the evaporation chamber through said opening so as to prevent flow of fuel droplets into the transverse bores during cold engine start, said fuel droplets being heated within the evaporation chamber to be evaporated for return flow through said cover opening and the transverse runners into the engine cylinders, said valve means being responsive to engine temperature to control flow through said cover opening to prevent excess heating of the air-fuel mixture as it pases through said induction passage once the engine has reached a predetermined temperature.
 3. A heated manifold assembly for use in evaporating fuel particles during cold engine starts comprising an intake manifold having carburetor riser bores therein and an induction passage for receiving air-fuel mixture from a carburetor, transverse runners in communication with said induction passage for directing the air-fuel mixture from the carburetor to the intake valves of the engine, a heat transfer box located below said riser bores in the floor of the intake manifold defining a fuel evaporation chamber, means forming a crossover passageway in said manifold for directing exhaust from the engine in heat transfer relationship with said box to raise the temperature thereof on cold engine start, means forming a cover over said box including a central opening therein underlying said riser bores, said cover including a pair of outlet openings therein for directing evaporated fuel from said evaporation chamber into said transverse runners, bimetallic valve means supported on said cover having a first operative position when the engine is cold to direct air-fuel mixture from the riser bores through the central opening of said cover into said evaporation chamber, thence outwardly of said cover outlets into said transverse runners whereby fuel droplets in the air-fuel mixture during cold engine start are evaporated prior to passage to the transverse runners, said valve means being responsive to a predetermined increase in engine temperature to assume a second operative position to close said outlet openings and to open direct communication between said induction passage and said transverse runners for reducing heat transfer from said box to the air-fuel mixture thereby to prevent excessive temperature increases therein following engine warm-up. 